EFM Oil Disconnect Hot Water

I want to install a stand alone water heater - how to disconnect furnace from starting for hot water (only need for heat in winter )

Pipe up the new water heater separately from the EFM....if you want to no longer use the EFM for DHW. If you want seasonal use of the EFM for DHW, you could shut down the separate unit,
or use it for additional storage with a circulator and aquastat to control the temp limits. Obviously you HAVE to protect the DHW with a mixing valve, but that should be on the EFM right now. More info needed, please
We need to know how the DHW coil is piped now. You will be adding a handful of gate valves, that's for sure.

I'm confused, you're running this year round and don't want to use it for hot water? If it's on you might as well heat the hot water with it.

In any event pipe the hot water from the EFM directly into the hot water heater and then.....

A)If you're turning the furnace off for the summer nothing more to do. We run it right into a hot water heater however the hot water heater is not on. We use enough water that it never gets cold enough to justify the electric usage. The only real reason for the hot water heater is in case something breaks on the boiler. In the summer you would turn the hot water heater on, turn it off in the winter as long as you keep enough hot water. If you don't use enough hot water set up a themosiphon loop, you can naturally circulate the hottest water into the hot water tank

B)if you're leaving the boiler on and don't want it to go through the coil set up a bypass with some valves but as I said above you might as well heat water with it.

flingman1 wrote:I want to install a stand alone water heater - how to disconnect furnace from starting for hot water (only need for heat in winter )

do you mean a boiler, with a summer-winter coil ? just change the triple acting aquastat, to a double acting, or install a 24 volt coil, single pole relay to control the 120 volt to the triple action, and tie the T T together with a small wire. burner and circ. will come on only with t-stat call. last method is cheaper.

Do not want EFM furnace to handle the hot water - never enough , has to run all summer burning oil as well as winter -- want to use furnace/boiler for heat only in winter & install stand alone high efficient water heater

flingman1 wrote:Do not want EFM furnace to handle the hot water - never enough , has to run all summer burning oil as well as winter -- want to use furnace/boiler for heat only in winter & install stand alone high efficient water heater

Okay, so this is NOT a Coal Unit...strictly oil...and you want to have plenty of DHW all seasons.

Did it ever make enough hot water?
Might be the internal coil has become scaled up inside and reducing its output capacity.
A good coil cleaning or outright coil replacement could get you back in business.
The idea to add an electric water heater to not burn oil in summer make sense.
Perhaps you would want to pre-heat the water into the electric water heater in the winter through the boiler.

flingman1 wrote:I want to install a stand alone water heater - how to disconnect furnace from starting for hot water (only need for heat in winter )

Remove electric power by turning off switch or circuit breaker.

I can see why you'd want to do that if you are only using OIL on the EFM.

Any thoughts of burning Coal instead? thats the way i'd go!

I myself also don't run my EFM in the summers though either. I just have two shut offs that route water feed into the EFM and out to the Hot water heater (much like Richard from the sounds of it)

That way when the EFM is running it makes plenty of hot water and the water heater doesn't turn on.

When the EFM is not in use I just turn off the valves and water from the feed diverts into the water heater directly without going into the furnace.

A third valve is on the feed side into the hot water tank that I open when not using EFM, Close when using EFM so all water directs into boiler

this unit never really made enough hot water for family with showers , dishwasher, washer & oil prices have been high for the last 5 years just want furnace/boiler to run in winter & use an electric one all year

I have the hot water outlet of the tankless unit feed a hot water heater. In the summer, I turn off the boiler and let the cold water go through the EFM and feed the electric hot water heater. In the winter, the EFM preheats the water before going to the hot water heater so it doesn't use much electricity. Works great! Basically, I have a big hot water capacitor to feed the wife's big tub.